Owen Paterson is a former Environment Secretary and is MP for Shropshire North.

Two startling facts leaped out of the newspaper headlines last. First, immigration has overtaken the economy as the most important issue facing the country, according to the respected pollsters YouGov. Second, despite predictions to the contrary, especially from the BBC, immigration from Romania and Bulgaria is now running at 50,000 a year.

The YouGov finding is extraordinary. All my adult life, the state of the economy and the closely related matter of unemployment have been the number one concern of the British people. Not so now. Every month since May, immigration has either tied with the economy as the country’s main worry or been in the lead. During September, it outscored the economy by 58 per cent to 48 per cent as the top priority of voters.

But after Labour’s abject 13-year failure to control our borders, during which four million people were allowed to enter the UK – an unprecedented influx – I can’t say I am too surprised. Understandably, given the pressures that this tidal wave of newcomers has imposed on our public services, job opportunities and wage levels, the public is hopping mad about the collective failure of the political class to get a grip on our borders.

An election is only just over four months away. It is a safe bet to assume that immigration will loom large in the political battle to come – and that victory will go to the party that offers the most convincing solution to the question of how to bring order to the chaos of the present arrangements.

Labour and the Liberal Democrats have nothing to offer. Ed Miliband recently tried to toughen his party’s stance. But his efforts provoked derision when they coincided with a leaked internal briefing paper for his MPs and activists telling them to “move the conversation on” if voters had the temerity to mention immigration.

As for the Lib Dems, I treasure the arrogant complacency of Vince Cable, the Business Secretary, airily dismissing the threat of a Romanian and Bulgarian influx as “just a scare story”. The latest numbers prove how wrong he was.

UKIP, with its victories in the European elections and two by-elections last year, has skilfully tapped into public fury over borderless Britain. But I fear that its answer – leave the European Union and introduce an Australian points system to control numbers – is another dead end. Immigration is not a binary issue of control or no control, membership of the EU, or no membership. It’s a complex global problem.

Essentially, as long as there are significant incentives to move, people will cross borders. As long as we are a rich nation, people will continue to come. While Romanian wages are one-eighth of UK wages, it’s worth the cheap air fare.

When controls are imposed, people find a way round them. Even in the US, where millions of “wetbacks” cross the porous Mexican border, nearly half the illegal immigrants are people who entered legitimately as tourists, as students or for business purposes and have overstayed. In the UK, there are over 30 million visitors each year and attempts to pull up the drawbridge, as UKIP would have us do, would simply lead to a massive surge in illegal immigration.

Yet for our economy to grow, we must welcome people with a whole variety of skills, be they fruit pickers or graduate doctors. This is the conundrum: accepting 260,000 net immigrants in a year is stretching our public services to their limit and is unsustainable, but our open economy needs immigration.

UKIP’s solution is simply to “leave the EU”. I can see many advantages in Britain quitting the EU. But that alone would not crack the immigration problem. Even if we were to leave, it is inconceivable that the UK could negotiate a trade deal with the EU that did not involve some agreement on freedom of movement.

Currently, 13 percent of the UK population are first generation immigrants. Norway and Switzerland, both outside the EU but with such agreements, have immigrant populations of nearly 15 and 23 per cent. UKIP’s preferred option, the Australian skills-based points system, has resulted in an immigrant population of 27 per cent. Immigration is driven by “push” and “pull” factors unique to each country. Shaping these is more effective than formal border controls.

David Cameron was right in November to address one of the key “pull” factors by promising to “make welfare reform an absolute requirement in renegotiation”. However, much of the problematic immigration into this country stems not from the EU but from the European Convention of Human Rights. Repeal of the Human Rights Act and adoption of a new Bill of Rights would set the UK free from the ECHR, helping us to address the “push” factors.

We would no longer be forced to allow family members to join migrants; we could remove illegal immigrants as we wished. It is ludicrous that we are unable to deport illegal immigrants from Calais, because our judges say that France is not a “safe” country for asylum seekers!

Some measures, particularly those to do with benefits, are permissible under existing EU law. But many more will require treaty change. The Lisbon Treaty has made this change more complicated; it will be extremely difficult to reach an agreement before 2017. As if this wasn’t enough, the member states (especially Germany) and the Brussels Commission have made it clear that free movement is “not negotiable”.

We can’t force them to give us treaty change without invoking Article 50 of the Lisbon Treaty. It is the only legally binding mechanism that we can use to enter formal negotiations on a new relationship. It allows two years for negotiations, so there would still be time for a referendum in 2017.

It is critical to remember that the economic single market and the political EU are not one and the same thing. We can participate in the market as members of the European Economic Area without being saddled with the EU as a political project. Those, such as the business chiefs of the CBI, who confuse the memberships of the single market and the EU are making a basic error and misleading the British people.

This is where UKIP is wrong. Desperate to control immigration from the EU, the party has rejected continued membership of the single market within the EEA – which would place our economy at risk. In fact, as a member of the EEA but not the EU, we would not be bound by the European Court of Justice and its rulings on our benefits system. But, crucially, we could introduce “Safeguard Measures”, giving us an “emergency brake” on excessive migration – an option not available to us in the EU. We would get the benefits to business and the economy of free movement, with real power over our borders.

Managing immigration is a question of balance. We cannot afford to bring down the shutters and cut ourselves off from the rest of the world – many of our industries need skilled immigrants to keep our economy growing. Remember, too, that enterprising migrants have started nearly half a million businesses, employing over eight million people. A managed immigration policy should recognise this.

UKIP’s policy of simply “leaving the EU” is nothing but a populist slogan. Implementing an intelligent policy of managed immigration will require guts, determination and attention to detail. The colourful characters running UKIP may have added to the gaiety of the nation during the festive season. But only a resolute Conservative government with a good working majority can begin to address these issues.